Some were hoping for a clear sign of economic improvement from last week's jobs numbers, which would have made it more likely that tapering could begin in September. But the muddy employment picture has caused investors to reconsider. Some are now betting the Fed will sit tight until October, or even next year.

Last week, the Fed wrapped up a two-day meeting with small tweaks to its policy statement. Its overall outlook for the economy barely budged.

The central bank characterized recent economic growth as "modest," a barely imperceptible tweak in language from June, when it called the recovery "moderate."

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Corporate earnings: Several companies are on tap to report earnings this week, including T-Mobile(TMUS), AOL(AOL), Time Warner(TWC), CVS Caremark(CVS), Walt Disney(DIS) and DISH Network(DISH).